Preheat and Prepare Pan: Preheat your oven to 350°F (175°C). Place the stick of butter in a 9x13-inch baking dish and let it melt in the oven while it preheats. Once melted, remove the dish and set it aside.

Mix Dry Ingredients: In a medium bowl, whisk together the flour, baking powder, salt, and sugar until well combined.

Combine Wet Ingredients: In another bowl, mix the buttermilk, vanilla extract, and lemon zest. Pour this mixture into the dry ingredients and stir until just combined, avoiding overmixing.

Pour Batter and Add Filling: Gently drizzle the batter over the melted butter in the baking dish, taking care not to mix them together. Gently spoon the lemon pie filling over the batter, distributing it evenly.

Bake the Cobbler: Bake for 40-45 minutes, or until the top is golden and a toothpick inserted into the crust comes out clean. The filling will sink to the bottom while the batter rises to the top, creating a layered cobbler.

Cool and Serve: Let the cobbler rest for a few minutes to cool slightly before serving. Serve warm with a scoop of vanilla ice cream or a dollop of whipped cream if desired.